Section 4TROUBLESHOOTINGTM 9-2320463-20-1D. CHART5. CHECK ENGINE LIGHT ON AND CODE 25 ON DDRNOTE  This chart is only to be used if:1 ) All basic mechanical checks and physical inspections have been performed with no problem found, and2) Diagnosis of DDEC-II was started at step Start-1 (page 3-121) and you have now been referred here.C5-1 Check for Short(Ckt #451)l Turn ignition on. observe CheckEngine light.l Start engine and increase RPMwith throttle and observe CheckEngine light.C5-2 Check for Short(Ckt #419)l Turn ignition off.l Disconnect the vehicle harnessconnector at the ECM.l Turn Ignition on (engine not running)while at the same time observingthe Check Engine" lightCS-3 Force CEL Onl Install a jumper wire between socketB1 of the vehicle harnessconnector and a good ground.l Observe "Check Engine lightRESULTIWHAT TO DO NEXTCheck for short to ground onDiagnostic Request (Ckt #451).Contact Direct Support.Then go to C5-30.Go to C5-2.CEL Driver line (ckt #419) isshorted to ground. Contact DirectSupport. Then go to C5-30.Go to C5-3Go to C5-4.The ignition line (ckt #439) is notcorrectly wired to the CEL bulb.See if the bulb has been wiredinto the ignition line (#439)instead of the proper #419 wireCorrect problem. Then go toC5-30.3-169